Successful treatment of severe cardiomyopathy in glycogen storage disease type III With D,L-3-hydroxybutyrate, ketogenic and high-protein diet

Galectin-3: a novel biomarker of glycogen storage disease type III

Glycogen storage disease type III (GSDIII) is a rare genetic disorder leading to abnormal glycogen storage in the liver and skeletal muscle. In this study, we conducted a comparative gene expression analysis of several in vitro and in vivo models and identified galectin-3 as a potential biomarker of the disease. Interestingly, we also observed a significant decrease in galectin-3 expression in mice treated with an AAV gene therapy. Finally, galectin-3 expression was studied in muscle biopsies of GSDIII patients, confirming its increase in patient tissue. Beyond the identification of this novel biomarker, our study offers a new perspective for future therapeutic developments.

Recurrence of Myopathy After Liver Transplantation for Patients With End-Stage GSD Type IIIa

BACKGROUND

Glycogen storage disease (GSD) is an inherited metabolic disorder affecting glycogen metabolism. The overall incidence of GSD is estimated to be 1 in every 20,000 to 43,000 newborns. GSD is classified into 12 types based on the enzyme deficiency and the tissues affected. Disorders in glycogen degradation may primarily impact the liver, muscles, or both.

RESULTS

In this case report, we discuss a patient with end-stage liver disease due to GSD IIIa who was treated with liver transplantation. Following liver transplantation, the patient's cirrhosis was cured. Six years post-surgery, the patient developed elevated creatine kinase levels without any obvious cause, along with occasional lower limb weakness after exertion. Muscle biopsy revealed pathological changes consistent with vacuolar myopathy.

CONCLUSIONS

Liver transplantation does not fully cure glycogen storage disease type IIIa myopathy, necessitating ongoing postoperative follow-up with regular creatine kinase monitoring and other laboratory assessments.

Personalized management of hepatic glycogen storage disorders: The role of continuous glucose monitoring

OBJECTIVE

Glycogen storage disorders (GSD), inherent disorders of carbohydrate metabolism, feature hypoglycemia as a hallmark. Normoglycemia and glucose monitoring are pivotal in disease management. Conventional glucometer-based monitoring may overlook hypoglycemic trends. This study assesses glycemic control in Asian Indian GSD children using continuous glucose monitoring (CGM) and its role in facilitating dietary adjustments.

METHODS

A pre-post study enrolled molecularly confirmed GSDI, GSDIII, GSDVI, and GSDIX patients for baseline dietary compliance and CGM-based glycemic status evaluation. Hypoglycemic patients were stratified into diet-compliant and diet-noncompliant groups. Noncompliant patients received dietary reinforcement; compliant individuals underwent dietary adjustments. Repeat CGM (rCGM) was performed 6 weeks to 6 months postadjustments. Clinical and metabolic parameters were re-evaluated at 6 months.

RESULTS

Of the 20 patients assessed at baseline, 11 were diet compliant. Six among these exhibited hypoglycemia, prompting diet adjustments. Among nine noncompliant patients, eight experienced hypoglycemia and received diet reinforcement. rCGM in 10 patients (five GSDI, three GSDIII, and two GSDIXc) showed a significant reduction in hypoglycemia duration in all. An improvement in height and body mass index was observed in all GSDI and GSDIII patients. Triglyceride levels, raised at baseline in two GSDI and one GSDIII, showed a substantial decline in one GSDI patient. Hepatic transaminase levels decreased in both GSDIXc patients. Plasma lactate levels decreased in all GSDI patients.

CONCLUSION

CGM is an efficacious adjunct in the personalized management of hepatic GSD patients, in the Asian Indian population. The study also underscores the need for long-term follow-up to determine the role of glycemic management in growth, general well-being, and metabolic control in the GSD subtypes.

Long-term personalized high-protein, high-fat diet in pediatric patients with glycogen storage disease type IIIa: Evaluation of myopathy, metabolic control, physical activity, growth, and dietary compliance

Dietary lipid manipulation has recently been proposed for managing glycogen storage disease (GSD) type IIIa. This study aimed to evaluate the myopathic, cardiac, and metabolic status, physical activity, growth, and dietary compliance of a personalized diet high in protein and fat for 24 months. Of 31 patients with type IIIa GSD, 12 met the inclusion criteria. Of these, 10 patients (mean age 11.2 ± 7.4 years) completed the study. Patients were prescribed a personalized high-protein, high-fat diet, comprising 3.0-3.5 g/kg/day of protein and 3.0-4.5 g/kg/day of fat, constituting 18.5%-28% and 70.5%-75.7% of daily energy, respectively. Dietary compliance was ensured and assessed via the regular administration of questionnaires. Our results revealed consistent and significant decreases of 22%, 54%, and 30% in the creatinine kinase, creatine kinase-myocardial band, and lactate dehydrogenase levels, respectively. Echocardiography revealed improvements in the Z-scores of the left ventricular mass and interventricular septum thickness. A significant increase in body muscle mass was observed, and a higher score was achieved using the Daily Activity Questionnaire. Growth monitoring revealed an arrest in the height-SDS at the 6th and 12th months, followed by subsequent improvement at the end of the second year. A gradual and persistent decline in the periods of hypo- and hyperglycemia has been reported. Biotinidase activity decreased, whereas hepatosteatosis increased and then decreased by the end of the study. Implementing a high-protein, high-fat diet and monitoring key parameters in patients with type IIIa GSD can lead to myopathic and cardiac improvements and increased physical activity.

The Autophagic Activator GHF-201 Can Alleviate Pathology in a Mouse Model and in Patient Fibroblasts of Type III Glycogenosis

Glycogen storage disease type III (GSDIII) is a hereditary glycogenosis caused by deficiency of the glycogen debranching enzyme (GDE), an enzyme, encoded by Agl, enabling glycogen degradation by catalyzing alpha-1,4-oligosaccharide side chain transfer and alpha-1,6-glucose cleavage. GDE deficiency causes accumulation of phosphorylase-limited dextrin, leading to liver disorder followed by fatal myopathy. Here, we tested the capacity of the new autophagosomal activator GHF-201 to alleviate disease burden by clearing pathogenic glycogen surcharge in the GSDIII mouse model Agl-/-. We used open field, grip strength, and rotarod tests for evaluating GHF-201's effects on locomotion, a biochemistry panel to quantify hematological biomarkers, indirect calorimetry to quantify in vivo metabolism, transmission electron microscopy to quantify glycogen in muscle, and fibroblast image analysis to determine cellular features affected by GHF-201. GHF-201 was able to improve all locomotion parameters and partially reversed hypoglycemia, hyperlipidemia and liver and muscle malfunction in Agl-/- mice. Treated mice burnt carbohydrates more efficiently and showed significant improvement of aberrant ultrastructural muscle features. In GSDIII patient fibroblasts, GHF-201 restored mitochondrial membrane polarization and corrected lysosomal swelling. In conclusion, GHF-201 is a viable candidate for treating GSDIII as it recovered a wide range of its pathologies in vivo, in vitro, and ex vivo.

Synergism of dual AAV gene therapy and rapamycin rescues GSDIII phenotype in muscle and liver

Glycogen storage disease type III (GSDIII) is a rare metabolic disorder due to glycogen debranching enzyme (GDE) deficiency. Reduced GDE activity leads to pathological glycogen accumulation responsible for impaired hepatic metabolism and muscle weakness. To date, there is no curative treatment for GSDIII. We previously reported that 2 distinct dual AAV vectors encoding for GDE were needed to correct liver and muscle in a GSDIII mouse model. Here, we evaluated the efficacy of rapamycin in combination with AAV gene therapy. Simultaneous treatment with rapamycin and a potentially novel dual AAV vector expressing GDE in the liver and muscle resulted in a synergic effect demonstrated at biochemical and functional levels. Transcriptomic analysis confirmed synergy and suggested a putative mechanism based on the correction of lysosomal impairment. In GSDIII mice livers, dual AAV gene therapy combined with rapamycin reduced the effect of the immune response to AAV observed in this disease model. These data provide proof of concept of an approach exploiting the combination of gene therapy and rapamycin to improve efficacy and safety and to support clinical translation.

[Fourteenth Jesús Culebras Lecture. Ketogenic diet, a half-discovered treatment]

Introduction

The ketogenic diet was an amazing approach to treating epilepsy from its beginning. The body undergoes a change in obtaining energy, going from depending on carbohydrates to depending on fats, and then a whole series of biochemical routes are launched that, independently but also complementary, give rise to a set of effects that benefit the patient. This search for its mechanism of action, of devising how to improve compliance and take advantage of it for other diseases has marked its trajectory. This article briefly reviews these aspects, emphasizing the importance of continuing to carry out basic and clinical research so that this treatment can be applied with solid scientific bases.

Nonlinear dynamics of estrogen receptor-positive breast cancer integrating experimental data: A novel spatial modeling approach

Oncology research has focused extensively on estrogen hormones and their function in breast cancer proliferation. Mathematical modeling is essential for the analysis and simulation of breast cancers. This research presents a novel approach to examine the therapeutic and inhibitory effects of hormone and estrogen therapies on the onset of breast cancer. Our proposed mathematical model comprises a nonlinear coupled system of partial differential equations, capturing intricate interactions among estrogen, cytotoxic T lymphocytes, dormant cancer cells, and active cancer cells. The model's parameters are meticulously estimated through experimental studies, and we conduct a comprehensive global sensitivity analysis to assess the uncertainty of these parameter values. Remarkably, our findings underscore the pivotal role of hormone therapy in curtailing breast tumor growth by blocking estrogen's influence on cancer cells. Beyond this crucial insight, our proposed model offers an integrated framework to delve into the complexity of tumor progression and immune response under hormone therapy. We employ diverse experimental datasets encompassing gene expression profiles, spatial tumor morphology, and cellular interactions. Integrating multidimensional experimental data with mathematical models enhances our understanding of breast cancer dynamics and paves the way for personalized treatment strategies. Our study advances our comprehension of estrogen receptor-positive breast cancer and exemplifies a transformative approach that merges experimental data with cutting-edge mathematical modeling. This framework promises to illuminate the complexities of cancer progression and therapy, with broad implications for oncology.

Nutritional Approach in Selected Inherited Metabolic Cardiac Disorders-A Concise Summary of Available Scientific Evidence

Inborn errors of metabolism (IMDs) are a group of inherited diseases that manifest themselves through a myriad of signs and symptoms, including structural or functional cardiovascular damage. The therapy of these diseases is currently based on enzyme-replacement therapy, chaperone therapy or the administration of supplements and the establishment of personalized dietary plans. Starting from the major signs identified by the pediatric cardiologist that can indicate the presence of such a metabolic disease-cardiomyopathies, conduction disorders or valvular dysplasias-we tried to paint the portrait of dietary interventions that can improve the course of patients with mitochondrial diseases or lysosomal abnormalities. The choice of the two categories of inborn errors of metabolism is not accidental and reflects the experience and concern of the authors regarding the management of patients with such diagnoses. A ketogenic diet offers promising results in selected cases, although, to date, studies have failed to bring enough evidence to support generalized recommendations. Other diets have been successfully utilized in patients with IMDs, but their specific effect on the cardiac phenotype and function is not yet fully understood. Significant prospective studies are necessary in order to understand and establish which diet best suits every patient depending on the inherited metabolic disorder. The most suitable imagistic monitoring method for the impact of different diets on the cardiovascular system is still under debate, with no protocols yet available. Echocardiography is readily available in most hospital settings and brings important information regarding the impact of diets on the left ventricular parameters. Cardiac MRI (magnetic resonance imaging) could better characterize the cardiac tissue and bring forth both functional and structural information.

French recommendations for the management of glycogen storage disease type III

The aim of the Protocole National De Diagnostic et de Soins/French National Protocol for Diagnosis and Healthcare (PNDS) is to provide advice for health professionals on the optimum care provision and pathway for patients with glycogen storage disease type III (GSD III).The protocol aims at providing tools that make the diagnosis, defining the severity and different damages of the disease by detailing tests and explorations required for monitoring and diagnosis, better understanding the different aspects of the treatment, defining the modalities and organisation of the monitoring. This is a practical tool, to which health care professionals can refer. PNDS cannot, however, predict all specific cases, comorbidities, therapeutic particularities or hospital care protocols, and does not seek to serve as a substitute for the individual responsibility of the physician in front of his/her patient.

Glycogen storage diseases: An update

Glycogen storage diseases (GSDs), also referred to as glycogenoses, are inherited metabolic disorders of glycogen metabolism caused by deficiency of enzymes or transporters involved in the synthesis or degradation of glycogen leading to aberrant storage and/or utilization. The overall estimated GSD incidence is 1 case per 20000-43000 live births. There are over 20 types of GSD including the subtypes. This heterogeneous group of rare diseases represents inborn errors of carbohydrate metabolism and are classified based on the deficient enzyme and affected tissues. GSDs primarily affect liver or muscle or both as glycogen is particularly abundant in these tissues. However, besides liver and skeletal muscle, depending on the affected enzyme and its expression in various tissues, multiorgan involvement including heart, kidney and/or brain may be seen. Although GSDs share similar clinical features to some extent, there is a wide spectrum of clinical phenotypes. Currently, the goal of treatment is to maintain glucose homeostasis by dietary management and the use of uncooked cornstarch. In addition to nutritional interventions, pharmacological treatment, physical and supportive therapies, enzyme replacement therapy (ERT) and organ transplantation are other treatment approaches for both disease manifestations and long-term complications. The lack of a specific therapy for GSDs has prompted efforts to develop new treatment strategies like gene therapy. Since early diagnosis and aggressive treatment are related to better prognosis, physicians should be aware of these conditions and include GSDs in the differential diagnosis of patients with relevant manifestations including fasting hypoglycemia, hepatomegaly, hypertransaminasemia, hyperlipidemia, exercise intolerance, muscle cramps/pain, rhabdomyolysis, and muscle weakness. Here, we aim to provide a comprehensive review of GSDs. This review provides general characteristics of all types of GSDs with a focus on those with liver involvement.

Nutritional management of glycogen storage disease type III: a case report and a critical appraisal of the literature

Glycogen storage disease Type III (GSD III) is an autosomal recessive disease due to the deficiency of the debranching enzyme, which has two main consequences: a reduced availability of glucose due to the incomplete degradation of glycogen, and the accumulation of abnormal glycogen in liver and cardiac/skeletal muscle. The role of dietary lipid manipulations in the nutritional management of GSD III is still debated. A literature overview shows that low-carbohydrate (CHO) / high-fat diets may be beneficial in reducing muscle damage. We present a 24-year GSD IIIa patient with severe myopathy and cardiomyopathy in whom a gradual shift from a high-CHO diet (61% total energy intake), low-fat (18%), high-protein (21%) to a low-CHO (32 %) high-fat (45%) / high-protein (23%) diet was performed. CHO was mainly represented by high-fiber, low glycemic index food, and fat consisted prevalently of mono and polyunsaturated fatty acids. After a 2-year follow-up, all biomarkers of muscle and heart damage markedly decreased (by 50-75%), glucose levels remained within the normal range and lipid profile was unchanged. At echocardiography, there was an improvement in geometry and left ventricular function. A low -CHO, high-fat, high-protein diet seems to be safe, sustainable and effective in reducing muscle damage without worsening cardiometabolic profile in GSDIIIa. This dietary approach could be started as early as possible in GSD III displaying skeletal/cardiac muscle disease in order to prevent/minimize organ damage.

Pathological modeling of glycogen storage disease type III with CRISPR/Cas9 edited human pluripotent stem cells

Introduction: Glycogen storage disease type III (GSDIII) is a rare genetic disease caused by mutations in the AGL gene encoding the glycogen debranching enzyme (GDE). The deficiency of this enzyme, involved in cytosolic glycogen degradation, leads to pathological glycogen accumulation in liver, skeletal muscles and heart. Although the disease manifests with hypoglycemia and liver metabolism impairment, the progressive myopathy is the major disease burden in adult GSDIII patients, without any curative treatment currently available. Methods: Here, we combined the self-renewal and differentiation capabilities of human induced pluripotent stem cells (hiPSCs) with cutting edge CRISPR/Cas9 gene editing technology to establish a stable AGL knockout cell line and to explore glycogen metabolism in GSDIII. Results: Following skeletal muscle cells differentiation of the edited and control hiPSC lines, our study reports that the insertion of a frameshift mutation in AGL gene results in the loss of GDE expression and persistent glycogen accumulation under glucose starvation conditions. Phenotypically, we demonstrated that the edited skeletal muscle cells faithfully recapitulate the phenotype of differentiated skeletal muscle cells of hiPSCs derived from a GSDIII patient. We also demonstrated that treatment with recombinant AAV vectors expressing the human GDE cleared the accumulated glycogen. Discussion: This study describes the first skeletal muscle cell model of GSDIII derived from hiPSCs and establishes a platform to study the mechanisms that contribute to muscle impairments in GSDIII and to assess the therapeutic potential of pharmacological inducers of glycogen degradation or gene therapy approaches.

Metabolic Cardiomyopathies and Cardiac Defects in Inherited Disorders of Carbohydrate Metabolism: A Systematic Review

Heart failure (HF) is a progressive chronic disease that remains a primary cause of death worldwide, affecting over 64 million patients. HF can be caused by cardiomyopathies and congenital cardiac defects with monogenic etiology. The number of genes and monogenic disorders linked to development of cardiac defects is constantly growing and includes inherited metabolic disorders (IMDs). Several IMDs affecting various metabolic pathways have been reported presenting cardiomyopathies and cardiac defects. Considering the pivotal role of sugar metabolism in cardiac tissue, including energy production, nucleic acid synthesis and glycosylation, it is not surprising that an increasing number of IMDs linked to carbohydrate metabolism are described with cardiac manifestations. In this systematic review, we offer a comprehensive overview of IMDs linked to carbohydrate metabolism presenting that present with cardiomyopathies, arrhythmogenic disorders and/or structural cardiac defects. We identified 58 IMDs presenting with cardiac complications: 3 defects of sugar/sugar-linked transporters (GLUT3, GLUT10, THTR1); 2 disorders of the pentose phosphate pathway (G6PDH, TALDO); 9 diseases of glycogen metabolism (GAA, GBE1, GDE, GYG1, GYS1, LAMP2, RBCK1, PRKAG2, G6PT1); 29 congenital disorders of glycosylation (ALG3, ALG6, ALG9, ALG12, ATP6V1A, ATP6V1E1, B3GALTL, B3GAT3, COG1, COG7, DOLK, DPM3, FKRP, FKTN, GMPPB, MPDU1, NPL, PGM1, PIGA, PIGL, PIGN, PIGO, PIGT, PIGV, PMM2, POMT1, POMT2, SRD5A3, XYLT2); 15 carbohydrate-linked lysosomal storage diseases (CTSA, GBA1, GLA, GLB1, HEXB, IDUA, IDS, SGSH, NAGLU, HGSNAT, GNS, GALNS, ARSB, GUSB, ARSK). With this systematic review we aim to raise awareness about the cardiac presentations in carbohydrate-linked IMDs and draw attention to carbohydrate-linked pathogenic mechanisms that may underlie cardiac complications.

Understanding the Pathogenesis of Cardiac Complications in Patients with Propionic Acidemia and Exploring Therapeutic Alternatives for Those Who Are Not Eligible or Are Waiting for Liver Transplantation

The guidelines for the management of patients affected by propionic acidemia (PA) recommend standard cardiac therapy in the presence of cardiac complications. A recent revision questioned the impact of high doses of coenzyme Q10 on cardiac function in patients with cardiomyopathy (CM). Liver transplantation is a therapeutic option for several patients since it may stabilize or reverse CM. Both the patients waiting for liver transplantation and, even more, the ones not eligible for transplant programs urgently need therapies to improve cardiac function. To this aim, the identification of the pathogenetic mechanisms represents a key point. Aims: This review summarizes: (1) the current knowledge of the pathogenetic mechanisms underlying cardiac complications in PA and (2) the available and potential pharmacological options for the prevention or the treatment of cardiac complications in PA. To select articles, we searched the electronic database PubMed using the Mesh terms "propionic acidemia" OR "propionate" AND "cardiomyopathy" OR "Long QT syndrome". We selected 77 studies, enlightening 12 potential disease-specific or non-disease-specific pathogenetic mechanisms, namely: impaired substrate delivery to TCA cycle and TCA dysfunction, secondary mitochondrial electron transport chain dysfunction and oxidative stress, coenzyme Q10 deficiency, metabolic reprogramming, carnitine deficiency, cardiac excitation-contraction coupling alteration, genetics, epigenetics, microRNAs, micronutrients deficiencies, renin-angiotensin-aldosterone system activation, and increased sympathetic activation. We provide a critical discussion of the related therapeutic options. Current literature supports the involvement of multiple cellular pathways in cardiac complications of PA, indicating the growing complexity of their pathophysiology. Elucidating the mechanisms responsible for such abnormalities is essential to identify therapeutic strategies going beyond the correction of the enzymatic defect rather than engaging the dysregulated mechanisms. Although these approaches are not expected to be resolutive, they may improve the quality of life and slow the disease progression. Available pharmacological options are limited and tested in small cohorts. Indeed, a multicenter approach is mandatory to strengthen the efficacy of therapeutic options.

Defining metabolic migraine with a distinct subgroup of patients with suboptimal inflammatory and metabolic markers

Emerging evidence suggest migraine is a response to cerebral energy deficiency or oxidative stress in the brain. Beta-hydroxybutyrate (BHB) is likely able to circumvent some of the meta-bolic abnormalities reported in migraine. Exogenous BHB was given to test this assumption and, in this post-hoc analysis, multiple metabolic biomarkers were identified to predict  clinical improvements. A randomized clinical trial, involving 41 patients with episodic migraine. Each treatment period was 12 weeks long, followed by eight weeks of washout phase / second run-in phase before entering the corresponding second treatment period. The primary endpoint was the number of migraine days in the last 4 weeks of treatment adjusted for baseline. BHB re-sponders were identified (those with at least a 3-day reduction in migraine days over placebo) and its predictors were evaluated using Akaike's Information Criterion (AIC) stepwise boot-strapped analysis and logistic regression. Responder analysis showed that metabolic markers could identify a "metabolic migraine" subgroup, which responded to BHB with a 5.7 migraine days reduction compared to the placebo. This analysis provides further support for a "metabolic migraine" subtype. Additionally, these analyses identified low-cost and easily accessible biomarkers that could guide recruitment in future research on this subgroup of patients.This study is part of the trial registration: ClinicalTrials.gov: NCT03132233, registered on 27.04.2017, https://clinicaltrials.gov/ct2/show/NCT03132233.

Improvement in hypertrophic cardiomyopathy after using a high-fat, high-protein and low-carbohydrate diet in a non-adherent child with glycogen storage disease type IIIa

Background

Glycogen storage diseases type IIIa and b (GSDIII) are rare inherited metabolic disorders that are caused by deficiencies of the glycogen debranching enzyme, resulting in the accumulation of abnormal glycogen (‘limit dextrin’) in the muscles. The cardiac storage of limit dextrin causes a form of cardiomyopathy similar to primary hypertrophic cardiomyopathy. Treatment with a high fat diet is controversial but we report a positive outcome in a child with cardiomyopathy.

Case presentation

A 9-year-old boy with GSDIIIa developed left ventricular hypertrophy at 4.3 years of age. A high-fat (50%), high protein (20%), low-carbohydrates (30%) diet was introduced. After 18 months, echocardiogram, biochemical and clinical parameters improved (Creatine Kinase (CK), 1628➔1125 U/L; left ventricular outflow tract (LVOT), 35➔20 mmHg; interventricular septum (IVS), 21➔10 mm). The diet was abandoned for 2 years resulting in reversal of symptoms, but recommencement showed improvement after 6 months.

Conclusion

A high fat, high protein and low carbohydrate diet was successful in reversing cardiomyopathy. This form of treatment should be considered in children with GSD IIIa with cardiomyopathy.

Neonatal Long-Chain 3-Ketoacyl-CoA Thiolase deficiency: Clinical-biochemical phenotype, sodium-D,L-3-hydroxybutyrate treatment experience and cardiac evaluation using speckle echocardiography

Isolated long-chain 3-keto-acyl CoA thiolase (LCKAT) deficiency is a rare long-chain fatty acid oxidation disorder caused by mutations in HADHB. LCKAT is part of a multi-enzyme complex called the mitochondrial trifunctional protein (MTP) which catalyzes the last three steps in the long-chain fatty acid oxidation. Until now, only three cases of isolated LCKAT deficiency have been described. All patients developed a severe cardiomyopathy and died before the age of 7 weeks. Here, we describe a newborn with isolated LCKAT deficiency, presenting with neonatal-onset cardiomyopathy, rhabdomyolysis, hypoglycemia and lactic acidosis. Bi-allelic 185G > A (p.Arg62His) and c1292T > C (p.Phe431Ser) mutations were found in HADHB. Enzymatic analysis in both lymphocytes and cultured fibroblasts revealed LCKAT deficiency with a normal long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD, also part of MTP) enzyme activity. Clinically, the patient showed recurrent cardiomyopathy, which was monitored by speckle tracking echocardiography. Subsequent treatment with special low-fat formula, low in long chain triglycerides (LCT) and supplemented with medium chain triglycerides (MCT) and ketone body therapy in (sodium-D,L-3-hydroxybutyrate) was well tolerated and resulted in improved carnitine profiles and cardiac function. Resveratrol, a natural polyphenol that has been shown to increase fatty acid oxidation, was also considered as a potential treatment option but showed no in vitro benefits in the patient's fibroblasts. Even though our patient deceased at the age of 13 months, early diagnosis and prompt initiation of dietary management with addition of sodium-D,L-3-hydroxybutyrate may have contributed to improved cardiac function and a much longer survival when compared to the previously reported cases of isolated LCKAT-deficiency.

A new phenotype of aldolase a deficiency in a 14 year-old boy with epilepsy and rhabdomyolysis - case report

Background

Glycogen storage disease type XII is a rare metabolic disease resulting from Aldolase A deficiency that causes muscle glycogen accumulation, with crisis of rhabdomyolysis and hemolytic anemia. In the very few cases described, rhabdomyolysis crises are caused by fever and/or exercise and can accompany acute hemolytic anemia. Although currently there is no therapy available for this disease, the guidelines for the management of other forms of glycogen storage diseases recommend a nutritional therapy in order to avoid hypoglycemia or prevent exercise-induced rhabdomyolysis.

Case presentation

In this case report we describe a new phenotype of the disease in a 14-year-old boy, characterized by seizures and rhabdomyolysis. Beside an antiepileptic treatment, we propose a new therapeutic approach based on ketogenic diet in order to supply an energetic substrate for skeletal muscle and neurons.

Conclusions

The anti-epileptic therapy and the dietetic approach were well tolerated by the patient who showed good compliance. This led to a deceleration of the disease with no other acute episodes of seizures and rhabdomyolysis, without any side effects observed.

Mathematical model for the estrogen paradox in breast cancer treatment

Estrogen is known to stimulate the growth of breast cancer, but is also effective in treating the disease. This is referred to as the"estrogen paradox". Furthermore, short-term treatment with estrogen can successfully eliminate breast cancer, whereas long-term treatment can cause cancer recurrence. Studies highlighted clinical correlations between estrogen and the protein p53 which plays a pivotal role in breast cancer suppression. We sought to investigate how the interplay between estrogen and p53 impacts the dynamics of breast cancer, and further explore if this could be a plausible explanation for the estrogen paradox and the paradoxical tumor recurrence that results from prolonged treatment with estrogen. For this, we propose a novel ODE based mathematical model that accounts for dormant and active cancer cells, along with the estrogen hormone and the p53 protein. We analyze the model's global stability behavior using the Poincaré-Bendixson theorem and results from differential inequalities. We also perform a bifurcation analysis and carry out numerical simulations that elucidate the roles of estrogen and p53 in the estrogen paradox and its long term estrogen paradoxical effect. The mathematical and numerical analyses suggest that the apparent paradoxical role of estrogen could be the result of an interplay between estrogen and p53, and provide explicit conditions under which the paradoxical effect of long-term treatment may be prevented.

Hypoglycaemia Metabolic Gene Panel Testing

A large number of inborn errors of metabolism present with hypoglycemia. Impairment of glucose homeostasis may arise from different biochemical pathways involving insulin secretion, fatty acid oxidation, ketone bodies formation and degradation, glycogen metabolism, fructose and galactose metabolism, branched chain aminoacids and tyrosine metabolism, mitochondrial function and glycosylation proteins mechanisms. Historically, genetic analysis consisted of highly detailed molecular testing of nominated single genes. However, more recently, the genetic heterogeneity of these conditions imposed to perform extensive molecular testing within a useful timeframe via new generation sequencing technology. Indeed, the establishment of a rapid diagnosis drives specific nutritional and medical therapies. The biochemical and clinical phenotypes are critical to guide the molecular analysis toward those clusters of genes involved in specific pathways, and address data interpretation regarding the finding of possible disease-causing variants at first reported as variants of uncertain significance in known genes or the discovery of new disease genes. Also, the trio's analysis allows genetic counseling for recurrence risk in further pregnancies. Besides, this approach is allowing to expand the phenotypic characterization of a disease when pathogenic variants give raise to unexpected clinical pictures. Multidisciplinary input and collaboration are increasingly key for addressing the analysis and interpreting the significance of the genetic results, allowing rapidly their translation from bench to bedside.

A retrospective longitudinal study and comprehensive review of adult patients with glycogen storage disease type III

INTRODUCTION

A deficiency of glycogen debrancher enzyme in patients with glycogen storage disease type III (GSD III) manifests with hepatic, cardiac, and muscle involvement in the most common subtype (type a), or with only hepatic involvement in patients with GSD IIIb.

OBJECTIVE AND METHODS

To describe longitudinal biochemical, radiological, muscle strength and ambulation, liver histopathological findings, and clinical outcomes in adults (≥18 years) with glycogen storage disease type III, by a retrospective review of medical records.

RESULTS

Twenty-one adults with GSD IIIa (14 F & 7 M) and four with GSD IIIb (1 F & 3 M) were included in this natural history study. At the most recent visit, the median (range) age and follow-up time were 36 (19-68) and 16 years (0-41), respectively. For the entire cohort: 40% had documented hypoglycemic episodes in adulthood; hepatomegaly and cirrhosis were the most common radiological findings; and 28% developed decompensated liver disease and portal hypertension, the latter being more prevalent in older patients. In the GSD IIIa group, muscle weakness was a major feature, noted in 89% of the GSD IIIa cohort, a third of whom depended on a wheelchair or an assistive walking device. Older individuals tended to show more severe muscle weakness and mobility limitations, compared with younger adults. Asymptomatic left ventricular hypertrophy (LVH) was the most common cardiac manifestation, present in 43%. Symptomatic cardiomyopathy and reduced ejection fraction was evident in 10%. Finally, a urinary biomarker of glycogen storage (Glc4) was significantly associated with AST, ALT and CK.

CONCLUSION

GSD III is a multisystem disorder in which a multidisciplinary approach with regular clinical, biochemical, radiological and functional (physical therapy assessment) follow-up is required. Despite dietary modification, hepatic and myopathic disease progression is evident in adults, with muscle weakness as the major cause of morbidity. Consequently, definitive therapies that address the underlying cause of the disease to correct both liver and muscle are needed.

Glycogen Debrancher Enzyme Deficiency Myopathy

ABSTRACT

Glycogen storage disease type III is a rare inherited disease caused by decreased activity of glycogen debranching enzyme. It affects primarily the liver, cardiac muscle, and skeletal muscle. Pure involvement of the skeletal muscle with adult onset is extremely rare. We report on a patient with myopathy due to glycogen storage disease III, and describe the clinical features, and pathologic and genetic findings.

Narrative review of glycogen storage disorder type III with a focus on neuromuscular, cardiac and therapeutic aspects

Glycogen storage disorder type III (GSDIII) is a rare inborn error of metabolism due to loss of glycogen debranching enzyme activity, causing inability to fully mobilize glycogen stores and its consequent accumulation in various tissues, notably liver, cardiac and skeletal muscle. In the pediatric population, it classically presents as hepatomegaly with or without ketotic hypoglycemia and failure to thrive. In the adult population, it should also be considered in the differential diagnosis of left ventricular hypertrophy or hypertrophic cardiomyopathy, myopathy, exercise intolerance, as well as liver cirrhosis or fibrosis with subsequent liver failure. In this review article, we first present an overview of the biochemical and clinical aspects of GSDIII. We then focus on the recent findings regarding cardiac and neuromuscular impairment associated with the disease. We review new insights into the pathophysiology and clinical picture of this disorder, including symptomatology, imaging and electrophysiology. Finally, we discuss current and upcoming treatment strategies such as gene therapy aimed at the replacement of the malfunctioning enzyme to provide a stable and long-term therapeutic option for this debilitating disease.

Metabolic epilepsies amenable to ketogenic therapies: Indications, contraindications, and underlying mechanisms

Metabolic epilepsies arise in the context of rare inborn errors of metabolism (IEM), notably glucose transporter type 1 deficiency syndrome, succinic semialdehyde dehydrogenase deficiency, pyruvate dehydrogenase complex deficiency, nonketotic hyperglycinemia, and mitochondrial cytopathies. A common feature of these disorders is impaired bioenergetics, which through incompletely defined mechanisms result in a wide spectrum of neurological symptoms, such as epileptic seizures, developmental delay, and movement disorders. The ketogenic diet (KD) has been successfully utilized to treat such conditions to varying degrees. While the mechanisms underlying the clinical efficacy of the KD in IEM remain unclear, it is likely that the proposed heterogeneous targets influenced by the KD work in concert to rectify or ameliorate the downstream negative consequences of genetic mutations affecting key metabolic enzymes and substrates-such as oxidative stress and cell death. These beneficial effects can be broadly grouped into restoration of impaired bioenergetics and synaptic dysfunction, improved redox homeostasis, anti-inflammatory, and epigenetic activity. Hence, it is conceivable that the KD might prove useful in other metabolic disorders that present with epileptic seizures. At the same time, however, there are notable contraindications to KD use, such as fatty acid oxidation disorders. Clearly, more research is needed to better characterize those metabolic epilepsies that would be amenable to ketogenic therapies, both experimentally and clinically. In the end, the expanded knowledge base will be critical to designing metabolism-based treatments that can afford greater clinical efficacy and tolerability compared to current KD approaches, and improved long-term outcomes for patients.

Effects of acute nutritional ketosis during exercise in adults with glycogen storage disease type IIIa are phenotype-specific: An investigator-initiated, randomized, crossover study

Glycogen storage disease type IIIa (GSDIIIa) is an inborn error of carbohydrate metabolism caused by a debranching enzyme deficiency. A subgroup of GSDIIIa patients develops severe myopathy. The purpose of this study was to investigate whether acute nutritional ketosis (ANK) in response to ketone-ester (KE) ingestion is effective to deliver oxidative substrate to exercising muscle in GSDIIIa patients. This was an investigator-initiated, researcher-blinded, randomized, crossover study in six adult GSDIIIa patients. Prior to exercise subjects ingested a carbohydrate drink (~66 g, CHO) or a ketone-ester (395 mg/kg, KE) + carbohydrate drink (30 g, KE + CHO). Subjects performed 15-minute cycling exercise on an upright ergometer followed by 10-minute supine cycling in a magnetic resonance (MR) scanner at two submaximal workloads (30% and 60% of individual maximum, respectively). Blood metabolites, indirect calorimetry data, and in vivo ³¹ P-MR spectra from quadriceps muscle were collected during exercise. KE + CHO induced ANK in all six subjects with median peak βHB concentration of 2.6 mmol/L (range: 1.6-3.1). Subjects remained normoglycemic in both study arms, but delta glucose concentration was 2-fold lower in the KE + CHO arm. The respiratory exchange ratio did not increase in the KE + CHO arm when workload was doubled in subjects with overt myopathy. In vivo ³¹ P MR spectra showed a favorable change in quadriceps energetic state during exercise in the KE + CHO arm compared to CHO in subjects with overt myopathy. Effects of ANK during exercise are phenotype-specific in adult GSDIIIa patients. ANK presents a promising therapy in GSDIIIa patients with a severe myopathic phenotype. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier: NCT03011203.

Preclinical Research in Glycogen Storage Diseases: A Comprehensive Review of Current Animal Models

GSD are a group of disorders characterized by a defect in gene expression of specific enzymes involved in glycogen breakdown or synthesis, commonly resulting in the accumulation of glycogen in various tissues (primarily the liver and skeletal muscle). Several different GSD animal models have been found to naturally present spontaneous mutations and others have been developed and characterized in order to further understand the physiopathology of these diseases and as a useful tool to evaluate potential therapeutic strategies. In the present work we have reviewed a total of 42 different animal models of GSD, including 26 genetically modified mouse models, 15 naturally occurring models (encompassing quails, cats, dogs, sheep, cattle and horses), and one genetically modified zebrafish model. To our knowledge, this is the most complete list of GSD animal models ever reviewed. Importantly, when all these animal models are analyzed together, we can observe some common traits, as well as model specific differences, that would be overlooked if each model was only studied in the context of a given GSD.

Increased Glucose Availability Attenuates Myocardial Ketone Body Utilization

Background Perturbations in myocardial substrate utilization have been proposed to contribute to the pathogenesis of cardiac dysfunction in diabetic subjects. The failing heart in nondiabetics tends to decrease reliance on fatty acid and glucose oxidation, and increases reliance on ketone body oxidation. In contrast, little is known regarding the mechanisms mediating this shift among all 3 substrates in diabetes mellitus. Therefore, we tested the hypothesis that changes in myocardial glucose utilization directly influence ketone body catabolism. Methods and Results We examined ventricular-cardiac tissue from the following murine models: (1) streptozotocin-induced type 1 diabetes mellitus; (2) high-fat-diet-induced glucose intolerance; and transgenic inducible cardiac-restricted expression of (3) glucose transporter 4 (transgenic inducible cardiac restricted expression of glucose transporter 4); or (4) dominant negative O-GlcNAcase. Elevated blood glucose (type 1 diabetes mellitus and high-fat diet mice) was associated with reduced cardiac expression of β-hydroxybutyrate-dehydrogenase and succinyl-CoA:3-oxoacid CoA transferase. Increased myocardial β-hydroxybutyrate levels were also observed in type 1 diabetes mellitus mice, suggesting a mismatch between ketone body availability and utilization. Increased cellular glucose delivery in transgenic inducible cardiac restricted expression of glucose transporter 4 mice attenuated cardiac expression of both Bdh1 and Oxct1 and reduced rates of myocardial BDH1 activity and β-hydroxybutyrate oxidation. Moreover, elevated cardiac protein O-GlcNAcylation (a glucose-derived posttranslational modification) by dominant negative O-GlcNAcase suppressed β-hydroxybutyrate dehydrogenase expression. Consistent with the mouse models, transcriptomic analysis confirmed suppression of BDH1 and OXCT1 in patients with type 2 diabetes mellitus and heart failure compared with nondiabetic patients. Conclusions Our results provide evidence that increased glucose leads to suppression of cardiac ketolytic capacity through multiple mechanisms and identifies a potential crosstalk between glucose and ketone body metabolism in the diabetic myocardium.

Genetic analysis and long-term treatment monitoring of 11 children with glycogen storage disease type IIIa

Objectives To investigate the clinical and genetic characteristics of children with glycogen storage disease type IIIa (GSD IIIa) and to explore the muscle involvement and manifestations of GSD IIIa patients. Methods The clinical data of 11 patients with GSD IIIa diagnosed by genetic testing from 2003 to 2019 were retrospectively analyzed. Results Twenty variants of AGL gene were detected in 11 patients, eight of which were novel variants. Before treatment, the height was significantly backward. All patients had hepatomegaly. Abnormal biochemical indicators were mainly manifested as significantly increased serum liver and muscle enzymes, accompanied by hypertriglyceridemia, hypoglycemia, hyperlactacidemia, slightly elevated pyruvic acid, and metabolic acidosis. After treatment, the height and liver size of the patients were significantly improved. At the same time, alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG), lactic acid and pyruvic acid in children were significantly decreased, while creatine kinase (CK) was significantly increased. During follow-up monitoring, six patients developed ventricular hypertrophy. Lactate dehydrogenase (LDH) (691.67 ± 545.27 vs. 362.20 ± 98.66), lactic acid (3.18 ± 3.05 vs. 1.10 ± 0.40), and pyruvic acid (64.30 ± 39.69 vs. 32.06 ± 4.61) were significantly increased in patients with ventricular hypertrophy compared with those without ventricular hypertrophy. Conclusions In clinical cases of upper respiratory tract infection or gastrointestinal symptoms accompanied by hypoglycemia, dyslipidemia, metabolites disorders, elevated serum liver, and muscle enzymes, the possibility of GSD IIIa should be vigilant. During treatment monitoring, if lactic acid, pyruvic acid, LDH, and CK rise, it indicates that the disease is not well controlled and there is the possibility of cardiac hypertrophy.

Beneficial Effects of Modified Atkins Diet in Glycogen Storage Disease Type IIIa

<b><i>Introduction:</i></b> Glycogen storage disease Type III (GSD III) is an autosomal recessive disease caused by the deficiency of glycogen debranching enzyme, encoded by the AGL gene. Two clinical types of the disease are most prevalent: GSD IIIa involves the liver and muscle, whereas IIIb affects only the liver. The classical dietetic management of GSD IIIa involves prevention of fasting, frequent feeds with high complex carbohydrates in small children, and a low-carb-high-protein diet in older children and adults. Recently, diets containing high amount of fat, including ketogenic and modified Atkins diet (MAD), have been suggested to have favorable outcome in GSD IIIa. <b><i>Methods:</i></b> Six patients, aged 3–31 years, with GSD IIIa received MAD for a duration of 3–7 months. Serum glucose, transaminases, creatine kinase (CK) levels, capillary ketone levels, and cardiac parameters were followed-up. <b><i>Results:</i></b> In all patients, transaminase levels dropped in response to MAD. Decrease in CK levels were detected in 5 out of 6 patients. Hypoglycemia was evident in 2 patients but was resolved by adding uncooked cornstarch to diet. <b><i>Conclusion:</i></b> Our study demonstrates that GSD IIIa may benefit from MAD both clinically and biochemically.

Dietary lipids in glycogen storage disease type III: A systematic literature study, case studies, and future recommendations

A potential role of dietary lipids in the management of hepatic glycogen storage diseases (GSDs) has been proposed, but no consensus on management guidelines exists. The aim of this study was to describe current experiences with dietary lipid manipulations in hepatic GSD patients. An international study was set up to identify published and unpublished cases describing hepatic GSD patients with a dietary lipid manipulation. A literature search was performed according to the Cochrane Collaboration methodology through PubMed and EMBASE (up to December 2018). All delegates who attended the dietetics session at the IGSD2017, Groningen were invited to share unpublished cases. Due to multiple biases, only data on GSDIII were presented. A total of 28 cases with GSDIII and a dietary lipid manipulation were identified. Main indications were cardiomyopathy and/or myopathy. A high fat diet was the most common dietary lipid manipulation. A decline in creatine kinase concentrations (n = 19, P < .001) and a decrease in cardiac hypertrophy in paediatric GSDIIIa patients (n = 7, P < .01) were observed after the introduction with a high fat diet. This study presents an international cohort of GSDIII patients with different dietary lipid manipulations. High fat diet may be beneficial in paediatric GSDIIIa patients with cardiac hypertrophy, but careful long-term monitoring for potential complications is warranted, such as growth restriction, liver inflammation, and hepatocellular carcinoma development.

Efficacy and safety of D,L-3-hydroxybutyrate (D,L-3-HB) treatment in multiple acyl-CoA dehydrogenase deficiency

PURPOSE

Multiple acyl-CoA dehydrogenase deficiency (MADD) is a life-threatening, ultrarare inborn error of metabolism. Case reports described successful D,L-3-hydroxybutyrate (D,L-3-HB) treatment in severely affected MADD patients, but systematic data on efficacy and safety is lacking.

METHODS

A systematic literature review and an international, retrospective cohort study on clinical presentation, D,L-3-HB treatment method, and outcome in MADD(-like) patients.

RESULTS

Our study summarizes 23 MADD(-like) patients, including 14 new cases. Median age at clinical onset was two months (interquartile range [IQR]: 8 months). Median age at starting D,L-3-HB was seven months (IQR: 4.5 years). D,L-3-HB doses ranged between 100 and 2600 mg/kg/day. Clinical improvement was reported in 16 patients (70%) for cardiomyopathy, leukodystrophy, liver symptoms, muscle symptoms, and/or respiratory failure. D,L-3-HB appeared not effective for neuropathy. Survival appeared longer upon D,L-3-HB compared with historical controls. Median time until first clinical improvement was one month, and ranged up to six months. Reported side effects included abdominal pain, constipation, dehydration, diarrhea, and vomiting/nausea. Median D,L-3-HB treatment duration was two years (IQR: 6 years). D,L-3-HB treatment was discontinued in 12 patients (52%).

CONCLUSION

The strength of the current study is the international pooling of data demonstrating that D,L-3-HB treatment can be effective and safe in MADD(-like) patients.

Dietary Management of the Glycogen Storage Diseases: Evolution of Treatment and Ongoing Controversies

The hepatic glycogen storage diseases (GSDs) are a group of disorders where abnormal storage or release of glycogen leads to potentially life-threatening hypoglycemia and metabolic disturbances. Dietary interventions have markedly improved the outcome for these disorders, from a previously fatal condition to one where people can do well with proper care. This article chronicles the evolution of dietary management and treatment of the hepatic GSDs (types 0, I, III, VI, IX, and XI). We examine historic and current approaches for preventing hypoglycemia associated with GSDs. There is a lack of consensus on the optimal dietary management of GSDs despite decades of research, and the ongoing controversies are discussed.

Administration of gamma-hydroxybutyrate instead of beta-hydroxybutyrate to a liver transplant recipient suffering from propionic acidemia and cardiomyopathy: A case report on a medication prescribing error

Beta‐hydroxybutyrate (BHB) is a synthetic ketone body used as an adjuvant energy substrate in the treatment of patients with metabolic cardiomyopathy. A medication prescribing error led to the administration of the general anesthetic sodium gamma‐hydroxybutyrate (GHB) instead of sodium BHB in a liver transplant recipient with propionic acidemia and cardiomyopathy, causing acute coma. A 15‐year‐old boy suffering from neonatal propionic acidemia underwent liver transplantation (LT) for metabolic decompensation and cardiomyopathy (treated with cardiotropic drugs and BHB) diagnosed a year previously. The patient had been rapidly extubated after LT, and was recovering well. Eight days after LT, the patient suddenly became comatose. No metabolic, immunological, hypertensive, or infectious complications were apparent. The brain magnetic resonance imaging and electroencephalography results were normal. The coma was soon attributed to a medication prescribing error: administration of GHB instead of BHB on day 8 post‐LT. The patient recovered fully within a few hours of GHB withdrawal. The computerized prescription system had automatically suggested the referenced anesthetic GHB (administered intravenously) instead of the non‐referenced ketone body BHB, triggering coma in our patient. A computerized prescription system generated a medication prescribing error for a rare disease, in which the general anesthetic GHB was mistaken for the nonreferenced energy substrate BHB.

The use of sodium DL-3-Hydroxybutyrate in severe acute neuro-metabolic compromise in patients with inherited ketone body synthetic disorders

Background

Ketone bodies form a vital energy source for end organs in a variety of physiological circumstances. At different times, the heart, brain and skeletal muscle in particular can use ketones as a primary substrate. Failure to generate ketones in such circumstances leads to compromised energy delivery, critical end-organ dysfunction and potentially death. There are a range of inborn errors of metabolism (IEM) affecting ketone body production that can present in this way, including disorders of carnitine transport into the mitochondrion, mitochondrial fatty acid oxidation deficiencies (MFAOD) and ketone body synthesis. In situations of acute energy deficit, management of IEM typically entails circumventing the enzyme deficiency with replenishment of energy requirements. Due to profound multi-organ failure it is often difficult to provide optimal enteral therapy in such situations and rescue with sodium DL-3-hydroxybutyrate (S DL-3-OHB) has been attempted in these conditions as documented in this paper.

Results

We present 3 cases of metabolic decompensation, one with carnitine-acyl-carnitine translocase deficiency (CACTD) another with 3-hydroxyl, 3-methyl, glutaryl CoA lyase deficiency (HMGCLD) and a third with carnitine palmitoyl transferase II deficiency (CPT2D). All of these disorders are frequently associated with death in circumstance where catastrophic acute metabolic deterioration occurs. Intensive therapy with adjunctive S DL-3OHB led to rapid and sustained recovery in all. Alternative therapies are scarce in these situations.

Conclusion

S DL-3-OHB has been utilised in multiple acyl co A dehydrogenase deficiency (MADD) in cases with acute neurological and cardiac compromise with long-term data awaiting publication. The use of S DL-3-OHB is novel in non-MADD fat oxidation disorders and contribute to the argument for more widespread use.

Ketogenic diets and protective mechanisms in epilepsy, metabolic disorders, cancer, neuronal loss, and muscle and nerve degeneration

Ketogenic diet (KD), the "High-fat, low-carbohydrate, adequate-protein" diet strategy, replacing glucose with ketone bodies, is effective against several diseases, from intractable epileptic seizures, metabolic disorders, tumors, autosomal dominant polycystic kidney disease, and neurodegeneration to skeletal muscle atrophy and peripheral neuropathy. Key mechanisms include augmented mitochondrial efficiency, reduced oxidative stress, and regulated phospho-AMP-activated protein kinase, gamma-aminobutyric acid-glutamate, Na^+/ K⁺ pump, leptin and adiponectin levels, ghrelin levels, lipogenesis, ketogenesis, lipolysis, and gluconeogenesis. In cancer cells, KD targets glucose metabolism, suppresses insulin-like growth factor-1 and PI3K/AKT/mTOR pathways, and reduces cancer cachexia and muscle waste and fatigue. An associated increased skeletal proliferator-activated receptor-γ coactivator-1α activity alters systemic ketone body homeostasis, contributing toward attenuated diabetic hyperketonemia. Antioxidative and anti-inflammatory properties enable KD enhance endurance and sports performances while preventing exercise-induced muscle and organ debility. KD reduces metabolic syndromes-associated allodynia and promotes peripheral axonal and sensory regeneration. This review enlightens effects of KD on various disease conditions. PRACTICAL APPLICATIONS: It is increasingly being realized that diet plays a very important role in our fight against several diseases. This can range from neurological disorders to diabetes and cancer. In this context, the potential of KD, the "High-fat, low-carbohydrate, adequate-protein" diet strategy, is increasingly being realized. In this article, we provide a comprehensive analysis of the benefits of KD against many diseases and discuss the underlying biochemical mechanisms. We hope that our write-up will stimulate further research on KD and help generate an interest for the populations to adopt this healthy diet. It can help overcome the problems associated with weight and dysregulated metabolism.

Deep morphological analysis of muscle biopsies from type III glycogenesis (GSDIII), debranching enzyme deficiency, revealed stereotyped vacuolar myopathy and autophagy impairment

Glycogen storage disorder type III (GSDIII), or debranching enzyme (GDE) deficiency, is a rare metabolic disorder characterized by variable liver, cardiac, and skeletal muscle involvement. GSDIII manifests with liver symptoms in infancy and muscle involvement during early adulthood. Muscle biopsy is mainly performed in patients diagnosed in adulthood, as routine diagnosis relies on blood or liver GDE analysis, followed by AGL gene sequencing. The GSDIII mouse model recapitulate the clinical phenotype in humans, and a nearly full rescue of muscle function was observed in mice treated with the dual AAV vector expressing the GDE transgene.

In order to characterize GSDIII muscle morphological spectrum and identify novel disease markers and pathways, we performed a large international multicentric morphological study on 30 muscle biopsies from GSDIII patients. Autophagy flux studies were performed in human muscle biopsies and muscles from GSDIII mice. The human muscle biopsies revealed a typical and constant vacuolar myopathy, characterized by multiple and variably sized vacuoles filled with PAS-positive material. Using electron microscopy, we confirmed the presence of large non-membrane bound sarcoplasmic deposits of normally structured glycogen as well as smaller rounded sac structures lined by a continuous double membrane containing only glycogen, corresponding to autophagosomes. A consistent SQSTM1/p62 decrease and beclin-1 increase in human muscle biopsies suggested an enhanced autophagy. Consistent with this, an increase in the lipidated form of LC3, LC3II was found in patients compared to controls. A decrease in SQSTM1/p62 was also found in the GSDIII mouse model.

In conclusion, we characterized the morphological phenotype in GSDIII muscle and demonstrated dysfunctional autophagy in GSDIII human samples.

These findings suggest that autophagic modulation combined with gene therapy might be considered as a novel treatment for GSDIII.

Ketone Administration for Seizure Disorders: History and Rationale for Ketone Esters and Metabolic Alternatives

The ketogenic diet (KD) is a high-fat, low-carbohydrate treatment for medically intractable epilepsy. One of the hallmark features of the KD is the production of ketone bodies which have long been believed, but not yet proven, to exert direct anti-seizure effects. The prevailing view has been that ketosis is an epiphenomenon during KD treatment, mostly due to clinical observations that blood ketone levels do not correlate well with seizure control. Nevertheless, there is increasing experimental evidence that ketone bodies alone can exert anti-seizure properties through a multiplicity of mechanisms, including but not limited to: (1) activation of inhibitory adenosine and ATP-sensitive potassium channels; (2) enhancement of mitochondrial function and reduction in oxidative stress; (3) attenuation of excitatory neurotransmission; and (4) enhancement of central γ-aminobutyric acid (GABA) synthesis. Other novel actions more recently reported include inhibition of inflammasome assembly and activation of peripheral immune cells, and epigenetic effects by decreasing the activity of histone deacetylases (HDACs). Collectively, the preclinical evidence to date suggests that ketone administration alone might afford anti-seizure benefits for patients with epilepsy. There are, however, pragmatic challenges in administering ketone bodies in humans, but prior concerns may largely be mitigated through the use of ketone esters or balanced ketone electrolyte formulations that can be given orally and induce elevated and sustained hyperketonemia to achieve therapeutic effects.

Application of metabolomics for unveiling the therapeutic role of traditional Chinese medicine in metabolic diseases

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional medicine has been practiced for thousands of years in China and some Asian countries. Traditional Chinese Medicine (TCM) is characterized as multi-component and multiple targets in disease therapy, and it is a great challenge for elucidating the mechanisms of TCM.

AIM OF THE REVIEW

Comprehensively summarize the application of metabolomics in biomarker discovery, stratification of TCM syndromes, and mechanism underlying TCM therapy on metabolic diseases.

METHODS

This review systemically searched the publications with key words such as metabolomics, traditional Chinese medicine, metabolic diseases, obesity, cardiovascular disease, diabetes mellitus in "Title OR Abstract" in major databases including PubMed, the Web of Science, Google Scholar, Science Direct, CNKI from 2010 to 2019.

RESULTS

A total of 135 papers was searched and included in this review. An overview of articles indicated that metabolic characteristics may be a hallmark of different syndromes/models of metabolic diseases, which provides a new perspective for disease diagnosis and therapeutic optimization. Moreover, TCM treatment has significantly altered the metabolic perturbations associated with metabolic diseases, which may be an important mechanism for the therapeutic effect of TCM.

CONCLUSIONS

Until now, many metabolites and differential biomarkers related to the pathogenesis of metabolic diseases and TCM therapy have been discovered through metabolomics research. Unfortunately, the biological role and mechanism of disease-related metabolites were largely unclarified so far, which warrants further investigation.

Challenges of Gene Therapy for the Treatment of Glycogen Storage Diseases Type I and Type III

Glycogen storage diseases (GSDs) type I (GSDI) and type III (GSDIII), the most frequent hepatic GSDs, are due to defects in glycogen metabolism, mainly in the liver. In addition to hypoglycemia and liver pathology, renal, myeloid, or muscle complications affect GSDI and GSDIII patients. Currently, patient management is based on dietary treatment preventing severe hypoglycemia and increasing the lifespan of patients. However, most of the patients develop long-term pathologies. In the past years, gene therapy for GSDI has generated proof of concept for hepatic GSDs. This resulted in a recent clinical trial of adeno-associated virus (AAV)-based gene replacement for GSDIa. However, the current limitations of AAV-mediated gene transfer still represent a challenge for successful gene therapy in GSDI and GSDIII. Indeed, transgene loss over time was observed in GSDI liver, possibly due to the degeneration of hepatocytes underlying the physiopathology of both GSDI and GSDIII and leading to hepatic tumor development. Moreover, multitissue targeting requires high vector doses to target nonpermissive tissues such as muscle and kidney. Interestingly, recent pharmacological interventions or dietary regimen aiming at the amelioration of the hepatocyte abnormalities before the administration of gene therapy demonstrated improved efficacy in GSDs. In this review, we describe the advances in gene therapy and the limitations to be overcome to achieve efficient and safe gene transfer in GSDs.

Potential Protective Mechanisms of Ketone Bodies in Migraine Prevention

An increasing amount of evidence suggests that migraines are a response to a cerebral energy deficiency or oxidative stress levels that exceed antioxidant capacity. The ketogenic diet (KD), a diet mimicking fasting that leads to the elevation of ketone bodies (KBs), is a therapeutic intervention targeting cerebral metabolism that has recently shown great promise in the prevention of migraines. KBs are an alternative fuel source for the brain, and are thus likely able to circumvent some of the abnormalities in glucose metabolism and transport found in migraines. Recent research has shown that KBs-D-β-hydroxybutyrate in particular-are more than metabolites. As signalling molecules, they have the potential to positively influence other pathways commonly believed to be part of migraine pathophysiology, namely: mitochondrial functioning, oxidative stress, cerebral excitability, inflammation and the gut microbiome. This review will describe the mechanisms by which the presence of KBs, D-BHB in particular, could influence those migraine pathophysiological mechanisms. To this end, common abnormalities in migraines are summarised with a particular focus on clinical data, including phenotypic, biochemical, genetic and therapeutic studies. Experimental animal data will be discussed to elaborate on the potential therapeutic mechanisms of elevated KBs in migraine pathophysiology, with a particular focus on the actions of D-BHB. In complex diseases such as migraines, a therapy that can target multiple possible pathogenic pathways seems advantageous. Further research is needed to establish whether the absence/restriction of dietary carbohydrates, the presence of KBs, or both, are of primary importance for the migraine protective effects of the KD.

Uniparental isodisomy of chromosome 1 results in glycogen storage disease type III with profound growth retardation

Background

Glycogen storage disease type III (GSDIII) is caused by mutations of AGL gene with debranching enzyme deficiency. Patients with GSDIII manifest fasting hypoglycemia, hepatomegaly, hepatopathy, myopathy, and cardiomyopathy. We report on an 18‐year‐old boy with a profound growth retardation (<3 SD) besides typical clinical features of GSDIII, whereby endocrinological studies were negative.

Methods and Results

Molecular analysis of AGL gene revealed the homozygous reported variant c.3903_3904insA. Since discordant results from segregation studies showed the carrier status in one parent only, SNP array and short tandem repeats analyses were performed, revealing a paternal disomy of chromosome 1 (UPD1).

Conclusion

This study describes the first case of GSDIII resulting from UPD1. UPD can play an important role even in case of imprinted genes. DIRAS3 is a maternally imprinted tumor suppressor gene, located on chromosome 1p31, and implicated in growth and oncogenesis. It can be speculated that DIRAS3 overexpression might have a role in the severe short stature of our patient. The study emphasizes the importance of parental segregation analysis especially in patients with recessive conditions to look for specific genetic causes of disease and to estimate properly the risk of family recurrence.

Diagnosis and management of glycogen storage diseases type VI and IX: a clinical practice resource of the American College of Medical Genetics and Genomics (ACMG)

PURPOSE

Glycogen storage disease (GSD) types VI and IX are rare diseases of variable clinical severity affecting primarily the liver. GSD VI is caused by deficient activity of hepatic glycogen phosphorylase, an enzyme encoded by the PYGL gene. GSD IX is caused by deficient activity of phosphorylase kinase (PhK), the enzyme subunits of which are encoded by various genes: ɑ (PHKA1, PHKA2), β (PHKB), ɣ (PHKG1, PHKG2), and δ (CALM1, CALM2, CALM3). Glycogen storage disease types VI and IX have a wide spectrum of clinical manifestations and often cannot be distinguished from each other, or from other liver GSDs, on clinical presentation alone. Individuals with GSDs VI and IX can present with hepatomegaly with elevated serum transaminases, ketotic hypoglycemia, hyperlipidemia, and poor growth. This guideline for the management of GSDs VI and IX was developed as an educational resource for health-care providers to facilitate prompt and accurate diagnosis and appropriate management of patients.

METHODS

A national group of experts in various aspects of GSDs VI and IX met to review the limited evidence base from the scientific literature and provided their expert opinions. Consensus was developed in each area of diagnosis, treatment, and management. Evidence bases for these rare disorders are largely based on expert opinion, particularly when targeted therapeutics that have to clear the US Food and Drug Administration (FDA) remain unavailable.

RESULTS

This management guideline specifically addresses evaluation and diagnosis across multiple organ systems involved in GSDs VI and IX. Conditions to consider in a differential diagnosis stemming from presenting features and diagnostic algorithms are discussed. Aspects of diagnostic evaluation and nutritional and medical management, including care coordination, genetic counseling, and prenatal diagnosis are addressed.

CONCLUSION

A guideline that will facilitate the accurate diagnosis and optimal management of patients with GSDs VI and IX was developed. This guideline will help health-care providers recognize patients with GSDs VI and IX, expedite diagnosis, and minimize adverse sequelae from delayed diagnosis and inappropriate management. It will also help identify gaps in scientific knowledge that exist today and suggest future studies.

Efficacy and safety of exogenous ketone bodies for preventive treatment of migraine: A study protocol for a single-centred, randomised, placebo-controlled, double-blind crossover trial

Background

Currently available prophylactic migraine treatment options are limited and are associated with many, often intolerable, side-effects. Various lines of research suggest that abnormalities in energy metabolism are likely to be part of migraine pathophysiology. Previously, a ketogenic diet (KD) has been reported to lead to a drastic reduction in migraine frequency. An alternative method to a strict KD is inducing a mild nutritional ketosis (0.4–2 mmol/l) with exogenous ketogenic substances. The aim of this randomised, placebo-controlled, double-blind, crossover, single-centre trial is to demonstrate safety and superiority of beta-hydroxybutyrate (βHB) in mineral salt form over placebo in migraine prevention.

Methods/design

Forty-five episodic migraineurs (5–14 migraine days/months), with or without aura, aged between 18 and 65 years, will be recruited at headache clinics in Switzerland, Germany and Austria and via Internet announcements. After a 4-week baseline period, patients will be randomly allocated to one of the two trial arms and receive either the βHB mineral salt or placebo for 12 weeks. This will be followed by a 4-week wash-out period, a subsequent second baseline period and, finally, another 12-week intervention with the alternative treatment. Co-medication with triptans (10 days per months) or analgesics (14 days per months) is permitted. The primary outcome is the mean change from baseline in the number of migraine days (meeting International Classification of Headache Disorders version 3 criteria) during the last 4 weeks of intervention compared to placebo. Secondary endpoints include mean changes in headache days of any severity, acute migraine medication use, migraine intensity and migraine and headache-related disability. Exploratory outcomes are (in addition to routine laboratory analysis) genetic profiling and expression analysis, oxidative and nitrosative stress, as well as serum cytokine analysis, and blood βHB and glucose analysis (pharmacokinetics).

Discussion

A crossover design was chosen as it greatly improves statistical power and participation rates, without increasing costs. To our knowledge this is the first RCT using βHB salts worldwide. If proven effective and safe, βHB might not only offer a new prophylactic treatment option for migraine patients, but might additionally pave the way for clinical trials assessing its use in related diseases.

Trial registration

ClinicalTrials.gov, NCT03132233. Registered on 27 April 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-3120-7) contains supplementary material, which is available to authorized users.

A preliminary study of telemedicine for patients with hepatic glycogen storage disease and their healthcare providers: from bedside to home site monitoring

BACKGROUND

The purpose of this project was to develop a telemedicine platform that supports home site monitoring and integrates biochemical, physiological, and dietary parameters for individual patients with hepatic glycogen storage disease (GSD).

METHODS AND RESULTS

The GSD communication platform (GCP) was designed with input from software developers, GSD patients, researchers, and healthcare providers. In phase 1, prototyping and software design of the GCP has occurred. The GCP was composed of a GSD App for patients and a GSD clinical dashboard for healthcare providers. In phase 2, the GCP was tested by retrospective patient data entry. The following software functionalities were included (a) dietary registration and prescription module, (b) emergency protocol module, and (c) data import functions for continuous glucose monitor devices and activity wearables. In phase 3, the GSD App was implemented in a pilot study of eight patients with GSD Ia (n = 3), GSD IIIa (n = 1), and GSD IX (n = 4). Usability was measured by the system usability scale (SUS). The mean SUS score was 64/100 [range: 38-93].

CONCLUSIONS

This report describes the design, development, and validation process of a telemedicine platform for patients with hepatic GSD. The GCP can facilitate home site monitoring and data exchange between patients with hepatic GSD and healthcare providers under varying circumstances. In the future, the GCP may support cross-border healthcare, second opinion processes and clinical trials, and could possibly also be adapted for other diseases for which a medical diet is the cornerstone.

A lower energetic, protein and uncooked cornstarch intake is associated with a more severe outcome in glycogen storage disease type III: an observational study of 50 patients

Background Glycogen storage disease type III (GSDIII), due to a deficiency of glycogen debrancher enzyme (GDE), is particularly frequent in Tunisia. Phenotypic particularities of Tunisian patients remain unknown. Our aim was to study complications of GSDIII in a Tunisian population and to explore factors interfering with its course. Methods A retrospective longitudinal study was conducted over 30 years (1986-2016) in the referral metabolic center in Tunisia. Results Fifty GSDIII patients (26 boys), followed for an average 6.75 years, were enrolled. At the last evaluation, the median age was 9.87 years and 24% of patients reached adulthood. Short stature persisted in eight patients and obesity in 19 patients. Lower frequency of hypertriglyceridemia (HTG) was associated with older patients (p<0.0001), higher protein diet (p=0.068) and lower caloric intake (p=0.025). Hepatic complications were rare. Cardiac involvement (CI) was frequent (91%) and occurred early at a median age of 2.6 years. Severe cardiomyopathy (50%) was related to lower doses of uncooked cornstarch (p=0.02). Neuromuscular involvement (NMI) was constant, leading to a functional discomfort in 64% of cases and was disabling in 34% of cases. Severe forms were related to lower caloric (p=0.005) and protein intake (p<0.015). Conclusions A low caloric, protein and uncooked cornstarch intake is associated with a more severe outcome in GSDIII Tunisian patients. Neuromuscular and CIs were particularly precocious and severe, even in childhood. Genetic and epigenetic factors deserve to be explored.